西藏朗错秋季裸鲤属营养生态位及种间食物关系

西藏朗错海拔4300 m,是典型的高原湖泊之一。湖内具有兰格湖裸鲤和拉孜裸鲤共存的现象。本研究采用碳、氮稳定同位素技术分析了2018年秋季兰格湖裸鲤和拉孜裸鲤的食物组成和营养生态位,探讨了两种裸鲤的种间食物关系,包括饵料相似性和重叠系数。结果表明: 兰格湖裸鲤主要摄食蜉蝣类幼虫、摇蚊类幼虫、着生藻类、钩虾类和浮游生物;拉孜裸鲤主要摄食蜉蝣类幼虫、着生藻类、摇蚊类幼虫、钩虾类和水生维管束植物。两种裸鲤的营养生态位存在重叠,兰格湖裸鲤的δ¹³C值变幅(CR=1.60)、δ¹⁵N值变幅(NR=1.89)和凸多边形,总面积(TA=1.80)均小于拉孜裸鲤,差值分别为0.09、0.57和1.29。两种裸鲤的饵料相似性系数(94.2％)和重叠系数(91.5%)均较高,表明秋季西藏朗错两种裸鲤可能存在激烈的种间食物竞争关系。     

Vigilance in Przewalski's gazelle: effects of sex, predation risk and group size

Vigilance in social animals is often aimed at detecting predators. Many social and environmental factors influence vigilance, including sex, predation risk and group size. During the summer of 2007, we studied Przewalski's gazelle Procapra przewalskii , an endemic ungulate to the Qinghai-Tibet Plateau, to test whether and how these three factors affect vigilance. We distinguished groups consisting of males, mothers with lambs and females without lambs making observations on groups in the presence or absence of nearby predators. We assessed the group-size effect on vigilance and how this varied with levels of predation risk and sex. Males and mothers scanned longer and with a higher frequency than females without lambs. Individuals were more vigilant under direct predation threat. Although vigilance generally decreased with group size, the extent of the decrease was independent of predation risk and was not significant in males. The results suggest that mothers are more vigilant suggesting greater vulnerability and that males may have increased their vigilance to compete for higher social ranks. The positive correlation between vigilance and predation risk and the negative correlation between vigilance and group size are consistent with earlier findings, but we failed to find an interaction between group size and predation risk on vigilance perhaps because vigilance levels are low even in small groups, thus making similar vigilant upward adjustments in both small and large groups.     

三种鼠尾草注射液对大鼠心肌缺血再灌注损伤的保护作用

本文研究了云南产鼠尾草属药物滇丹参、甘西鼠尾、褐毛甘西鼠尾对急性心肌缺血再灌注损伤的保护作用 ,并与丹参进行对比其疗效的相似性。结扎大鼠冠脉左前降支 ,30分钟后剪断结扎线造成心肌缺血再灌注模型 ,经股静脉给药。测定再灌注 6 0分钟后血清中CK、LDH、SOD、GSH -Px和MDA含量。结果滇丹参、甘西鼠尾、褐毛甘西鼠尾可以显著降低心肌缺血再灌注后血清CK、LDH和MDA含量 ,升高血清SOD和GSH -Px活力 (P <0 0 1,P <0 0 5 ) ,与丹参有相似的抗心肌缺血再灌注损伤作用。     

色林错裸鲤的年轮特征

本文描述了色林错裸鲤 (Gymnocyprisselincuoensis)的臀鳞、背鳍条磨片和耳石磨片上的生长标志及特征 ,指出色林错裸鲤臀鳞上的繁殖痕迹 ,以及耳石磨片早期生长中出现类似月周期的生长阻断、光镜下透明带中日生长增长的减少甚至消失等现象与色林错裸鲤的繁殖习性及多变的高原环境相关。在 5种年龄鉴定的材料中 ,以耳石磨片上的轮纹特征最为明显、清晰且规律性强 ,是最好的年龄解释材料 ,而鳃盖骨和脊椎骨上都只能观察到少数几个轮纹 ,并不适合用作年龄鉴定的材料。     

Semi-captive Przewalski's gazelles cope with winter adversity by adjusting their gut bacterial communities

The intestinal microbiota plays an important role in the digestion and absorption of nutrients in animals. To address the challenge of conservation, many endangered wildlife are kept in captive or semi-captive conditions. Numerous studies have been conducted on the intestinal microbiota of captive animals, but little information is available on the intestinal microbiota of semi-captive animals, such as Przewalski's gazelle (Procapra przewalskii), which is an endangered ungulate species only distributed around Qinghai Lake in China. In this study, we used high-throughput sequencing methods to analyze the gut bacterial community of semi-captive Przewalski's gazelles during summer and winter. There were differences in the gut bacterial community composition between the 2 seasons, with higher bacterial diversity in winter. Deterministic processes dominated the bacterial community assembly in both seasons. There was a greater influence of heterogeneous selection in winter compared to summer, suggesting that there was more intestinal environmental filtering and selection on shaping the gut bacterial community during winter. There were more potential probiotic bacteria and fewer potential pathogens in winter compared to summer. Overall, stronger heterogeneous selection in winter might enhance gut selection for potential probiotic bacteria and filter out potential pathogens in Przewalski's gazelles, allowing them to adapt to the harsh living conditions in winter. Our study clarified that seasonal fluctuations trigger shifts in bacterial communities, which have potential benefits for Przewalski's gazelles. These results could provide valuable information for managing semi-captive populations and for future wild releases of Przewalski's gazelles.     

荒漠沙蜥冬眠前与冬眠中期肝脏、胰腺、脂肪体超微结构的比较

对荒漠沙蜥（Phrynocephalus przewalskii）冬眠前及冬眠中期的肝脏、胰腺和脂肪体的超微结构进行了比较观察。结果表明,荒漠沙蜥肝脏、胰腺和脂肪体中的糖原颗粒、脂滴、内质网、线粒体等细胞结构有明显变化。冬眠中期胰腺腺泡细胞线粒体中出现致密颗粒,核周间隙增宽,核中出现无定形体。文中对上述结果的生理意义进行了讨论。     

Interspecific pollen transfer between two coflowering species was minimized by bumblebee fidelity and differential pollen placement on the bumblebee body

Aims When sympatric flowering plant species in a natural community share pollinators, study of plant–plant interactions via interspecific pollen transfer (IPT) is essential for understanding species coexistence. However, little is known about the extent of IPT between interactive species and its causes.Methods To explore how sympatric flowering plants sharing pollinators minimize deleterious effects of IPT, we investigated the pollination ecology of two endemic species, Salvia przewalskii and Delphinium yuanum, in an alpine meadow in the Hengduan Mountains, southwest China. We quantified conspecific and interspecific visits by shared bumblebee pollinators, amounts of pollen placed on different body sites of the pollinators and stigmatic pollen loads on open-pollinated flowers. To examine whether IPT affects female fitness, we measured pollen germination and seed production in the two species in an artificial pollination experiment.Important findings One bumblebee species, Bombus trifasciatus, was found to be the sole effective pollinator for the two coflowering species. Pollination experiments indicated that deposition of heterospecific pollen could significantly decrease seed set in both species. Experiments showed that S. przewalskii pollen could germinate well on stigmas of D. yuanum, inhibiting conspecific pollen germination in D. yuanum. However, seed set was not lower under open pollination than under cross-pollination within species, suggesting that no female fitness loss was caused by IPT. In foraging bouts with pollinator switches, switches from S. przewalskii to D. yuanum were relatively more frequent (8.27%) than the converse (1.72%). However, IPT from S. przewalskii to D. yuanum accounted for only 1.82% of total stigmatic pollen loads while the reverse IPT to S. przewalskii was 8.70%, indicating that more switches of bumblebees to D. yuanum did not result in higher IPT. By contrast, selection for reduced IPT to S. przewalskii would limit pollinator switches from D. yuanum. We found that a bumblebee generally carried pollen grains from both species but the two species differed in the position of pollen placement on the bumblebee's body; S. przewalskii ' s pollen was concentrated on the dorsal thorax while D. yuanum ' s pollen was concentrated ventrally on the head. This differential pollen placement along with pollinator fidelity largely reduced IPT between the two species with a shared pollinator.     

稀有植物裸果木的组织培养及植株再生

对稀有植物裸果木进行组织培养研究,在MS培养基上裸果木的下胚轴脱分化形成愈伤组织,并进一步分化形成再生植株。激素种类及其浓度是器官脱分化与植株再生的决定因素。诱导下胚轴形成愈伤组织的最适培养基为MS 1mg／L 6-BA 0．5mg／L NAA;芽分化诱导的最适培养基为MS 1 mg／L6-BA;生根的最适培养基为不含任何激素的1／2MS培养基。     

不同海拔高度祁连圆柏和青海云杉叶片色素的变化特征

利用高效液相色谱法(high performance liquid chromatography,HPLC)和酶标仪等测定了祁连山区不同海拔高度下祁连圆柏(Sabina przewalskii)和青海云杉(Picea crassifolia)叶片中色素含量、花青苷合成酶苯丙氨酸解氨酶(phenylalanine ammonialyase,PAL)和类黄酮糖基转移酶(UDP glucose-flavonoid 3-O-glucosyFtransferase,UFGT)活性.结果表明:两树种花青苷(anthocyanin,Acy)含量除了在海拔高度3100-3200 m有所升高外,总体上随海拔高度上升而降低;UFGT活性除了在3000 m左右波动外,总体随海拔高度上升而升高;祁连圆柏PAL活性随海拔高度上升而升高,青海云杉PAL活性在海拔2800-3000 m时,随海拔高度上升而升高,当海拔高度高于3000 m时,随海拔高度上升而降低两树种紫松果黄素(rhodoxanthin,Rhd)含量、叶黄素循环(xanthophyll cycle,VAZ)的脱环氧化程度(A+Z)/(V+A+Z)比值和类胡萝卜素(carotenoids,Car)含量随海拔高度上升而升高;叶绿素(chlorophyll,Chl)含量随海拔高度上升而降低.除叶绿素含量和PAL活性外,其它指标都是祁连圆柏高于青海云杉,尤其是UFGT活性祁连圆柏是青海云杉的2倍多.不同海拔梯度、不同季节植物遭受的主导胁迫因子不同,8月份祁连山两树种主要受干旱和强光胁迫,色素主要发挥抗旱和抗辐射作用.由此说明植物色素在不同生境、不同季节发挥的作用不同.